Such a turbine is known from DE 103 37 495 A1. It comprises in the usual manner a turbine wheel, which is rotatably arranged about an axis of rotation in a turbine housing. The turbine is equipped with a geometry adjusting device for performance control, with the help of which a geometry of the turbine wheel on the inflow side can be adjusted. Such a geometry adjusting device is usually also referred to as a variable turbine geometry. Accordingly, the turbine comprises a radial inflow channel that is arranged coaxially to the turbine wheel, which leads to a radial inlet region of the turbine wheel and which on the one hand is axially bounded by a blade carrier and on the other hand is axially bounded by a cover disc. On the blade carrier, multiple guide blades are pivotably arranged. By pivoting the guide blades, the flow geometry in the inflow channel, i.e. on the inflow side of the turbine wheel, can be adjusted. Furthermore, multiple spacer elements are arranged in the inflow channel, which axially project from the blade carrier and which adjust a predetermined spacing between blade carrier and cover disc. In addition, the turbine is equipped with an axial outflow channel that is arranged coaxially to the turbine wheel, which leads from the inlet region to an axial outlet region of the turbine wheel and which comprises an inner contour which is formed complementarily to the outer contour of the rotating turbine wheel and extends from the inlet region to the outlet region.
For the efficiency of the turbine, as narrow as possible a radial gap between the housing-sided inner contour and the outer contour of the turbine wheel is required. Here, thermally-related expansion effects on the one hand can determine the gap size. On the other hand, contaminations carried along in the exhaust gas can be deposited on the inner contour. To avoid these problems, the inner contour is formed on a contour sleeve that is separate with respect to the turbine housing, and which is connected to the cover disc in a fixed manner. In the known turbine, the contour sleeve is integrally moulded on the cover disc. In the mounted state, the cover disc loosely contacts the turbine housing axially. In the known turbine, the cover disc with inner contour moulded thereon is connected to the blade carrier in a fixed manner, which in turn is connected to the turbine housing in a fixed manner. The fixed connection between cover disc and blade carrier in this case is effected by means of screw connections, which are formed in the region of the space elements.
It has been shown that a fixed connection between cover disc and blade carrier can be disadvantageous during the heating-up of the turbine. In particular, the components which are fastened to one another can be distorted relative to one another during rapid heating-up, which increases wear and the risk of damages.